Workbench infrastructure

This required a small change to the top-level info.json spec, namely it requires a metadata.type = "workbench" field, and all of the "path" values referring to runs were changed from absolute URLs to relative paths from the top level file.
You skip the all purpose of the view factory using that.
It does not scale with the increasing set of data types. Each time a new data come into play that will require code change which is bad.